The field of this invention is data storage systems. More particularly, the invention pertains to plastic and plastic composite substrates used as discs in magneto-optical (MO) and magnetic recording (MR) data storage systems.
With the advance of magneto-optical and magnetic recording technologies, the design of the discs, and particularly the substrates, in such data storage systems have been the subject of great interest. One area of interest is the development of discs that can store increased densities of data. This can be achieved by formatting the disc with a particular pattern which provides for servo control. Formatting is done by forming a pattern of pits or grooves in the surface of the disk or substrate.
To provide formatting requires the use of a plastic substrate. Conventional hard discs, such as those used with MR systems, are made of aluminum or glass. Conventional CD""s do use polycarbonate plastic substrates; however, such applications are limited to low density storage, and to low rotation speeds of only a few thousand rpm. Further, such polycarbonate substrates are not suitable for use with a xe2x80x9cflyingxe2x80x9d recording head as used with MR and MO data storage systems, because of its low modulus and low damping properties giving poor shock and vibration performance.
The inventors have found that when substrates made from polycarbonate, or other materials such as amorphous polyolefin that have similar physical and mechanical properties to polycarbonate, are used in a MR or MO disk drive applications the substrate is prone to failure causing the disk drive to fail. The MR and MO disk drive applications typically employ rotation speeds of greater than 5000 rmp and utilize flying recording heads, and when using conventional polycarbonate and similar substrates, the head to disk tracking becomes very difficult for the servo system to accommodate due to axial and radial disk vibrations.
Thus, the currently available plastic substrates are unsatisfactory for MR and MO applications. Accordingly, it is desirable to provide a data storage system which addresses the aforementioned limitations, and in particular to provide a disk or substrate which is capable of formatting for high density data storage and is operable at high rotational speeds with flying heads.
Accordingly, it is an object of the present invention to provide an improved storage system or recording device.
More particularly, it is an object of the present invention to provide a plastic or plastic composite substrate that is used as a disk in MO or MR data storage systems.
These and other objects and advantages are achieved by the present invention disclosed herein where a data storage system substrate is provided, comprising at least one plastic material. The plastic material has mechanical strength and rigidity, and in particular it exhibits a modulus of about 350 kpsi or greater. In another aspect of the invention, the plastic material includes a damping agent for damping shock and/or vibration forces that the disk may be subject to during its operation. In another aspect of the invention a data storage system is provided having means for reading and writing information to a storage disk, and means for storing said information in said storage disk, wherein said storage disk is comprised of at least one plastic or plastic composite material, and the plastic or plastic composite material exhibits a modulus of about 350 kpsi or greater.
In another aspect of the invention, an apparatus is provided comprising a disk drive spindle motor; and at least one data storage disk mounted on the disk drive spindle having means for exhibiting a modulus of about 350 kpsi or greater. Further the apparatus includes means for strengthening and/or damping energy that the apparatus is subjected to.